Which of the following is true concerning Roth IRA conversions?

There are never any tax consequences for a Roth conversion.

Recharacterizations are permitted to unwind $($reverse$)$ a Roth conversation after $2017$ due to the TCJA of $2017.$

Conversions from non$-$deductible IRAs are the only conversions permitted.

A backdoor Roth conversion allows indivduals with excess income to fund Roth IRAs.